This invention relates to a system for processing feed pellets for poultry and livestock, and more particularly, to spray chambers for coating feed pellets during processing.
Processing systems for manufacturing feed pellets for poultry and livestock are well known. Of increasing importance within this industry is the usage of liquid additives. These additives include amino acids, vitamins, flavors, mold inhibitors, pellet binders, antioxidants, drugs and enzymes. In some pellet processing systems, these liquid additives are applied as a coating to finished pellets prior to directing the pellet stream to a bin for storage. Typically, the pellets are provided either by gravity feed or motorized conveyor to a control gate which selectively opens to drop pellets through a spray chamber. The spray chamber is a volumetric structure typically having nozzles mounted along at least one wall of the spray chamber. These nozzles are coupled to pumps that provide liquid additives from a reservoir to the nozzles so the liquid additives are dispensed under pressure from the nozzles to coat the pellets as they fall through the spray chamber. The coated pellets typically fall into a hopper that has a motor-driven auger mounted at its lowest end for transporting the coated pellets to a conveyor belt for routing to storage bins.
One of the problems with these types of systems is the need to periodically shut down the processing equipment and clean the spray chamber. The cleaning of the spray chamber is required because liquid additives, which miss pellets in the stream as they fall through the spray chamber, adhere to the wall opposing the nozzles of the spray chamber. Of course, the down-time associated with the cleaning of the spray chamber impacts the utilization of the pellet processing system and its economic efficiency. To extend the time between spray chamber cleanings, nozzles are typically placed at an angle on the high side of the spray chamber to reduce the likelihood that the spray has sufficient energy to reach the opposing wall if it passes through the pellet stream without contacting one or more pellets in the stream. A typically rule of thumb for placement of nozzles is the use of one nozzle for each two to three feet of spray chamber length. While careful placement of the nozzles somewhat increases the time between spray chamber cleanings, these cleanings are still required on a regular basis.
What is needed is a system that substantially reduces the need for spray chamber cleanings in a feed pellet processing system.
The above-limitations of previously known feed pellet processing systems are overcome by the dry mass flow meter/spray chamber combination of the present invention. The system of the present invention includes a dry mass flow meter operatively coupled to a hopper for livestock and poultry feed pellet flow and a spray chamber mounted proximate to the outlet of the dry mass flow meter so the pellets strike the side wall of the spray chamber that oppose the nozzles of the spray chamber at a position where spray that misses the pellets in the pellet stream impinge on the spray chamber side wall. That is, the spray chamber is located so the pellet flow leaving the dry mass flow meter strikes the side wall of the spray chamber that opposes the nozzles located within the spray chamber so the pellets frictionally clean the chamber side wall of liquid additives emitted from the nozzles. In this manner, the cleaning action of the pellets substantially reduces the need for cleaning the spray chamber as the flow of pellets through the spray chamber removes the liquid additive and assists in the coating of the pellets within the spray chamber. The dry mass flow meter of the present invention provides a wide, relatively thin ribbon of pellets to be presented close to the wall of the spray chamber that opposes the nozzles to provide a more even distribution of the pellets for coating and to better protect the side wall from overspray coating.
The system of the present invention incorporates the cleaning capability of pellet flow that has previously been ignored in other feed processing systems. In other systems, pellet flow was not placed proximate to the opposing side wall as prior systems placed the flow of pellets closer to the center of the spray chamber to reduce the likelihood that overspray would reach the opposing side wall and coat the wall. The present invention is counter to that principle and utilizes the pellet stream itself to provide cleaning action for the spray chamber and substantially increase the time between spray chamber cleanings, if necessary at all.
These and other advantages and benefits of the present invention may be ascertained from the detailed description of the invention in the accompanying drawings.